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Genome-wide platelet transcriptomics is increasingly used to uncover new aspects of platelet biology and as a diagnostic and prognostic tool. Nevertheless, platelet isolation methods for transcriptomic studies are not standardized, introducing challenges for cross-study comparisons, data integration, and replication. In this prospective multicenter study, called “Standardizing Platelet Transcriptomics for Discovery, Diagnostics, and Therapeutics in the Thrombosis and Hemostasis Community (STRIDE)” by the International Society on Thrombosis and Haemostasis Scientific and Standardization Committees, we assessed how 3 of the most commonly used platelet isolation protocols influence metrics from next-generation bulk RNA sequencing and functional assays. Compared with washing alone, more stringent removal of leukocytes by anti-CD45 beads or PALL filters resulted in a sufficient quantity of RNA for next-generation sequencing and similar quality of RNA sequencing metrics. Importantly, stringent removal of leukocytes resulted in the lower relative expression of known leukocyte-specific genes and the higher relative expression of known platelet-specific genes. The results were consistent across enrolling sites, suggesting that the techniques are transferrable and reproducible. Moreover, all 3 isolation techniques did not influence basal platelet reactivity, but agonist-induced integrin αIIbβ3activation is reduced by anti-CD45 bead isolation compared with washing alone. In conclusion, the isolation technique chosen influences genome-wide transcriptional and functional assays in platelets. These results should help the research community make informed choices about platelet isolation techniques in their own platelet studies.

Scientific and clinical interest in extracellular vesicles (EVs) is growing. EVs that expose tissue factor (TF) bind factor VII/VIIa and can trigger coagulation. Highly procoagulant TF-exposing EVs are detectable in the circulation in various diseases, such as sepsis, COVID-19, or cancer. Many in-house and commercially available assays have been developed to measure EV-TF activity and antigen, but only a few studies have compared some of these assays.

Proprotein convertase subtilisin/kexin 9 (PCSK9) is responsible for the degradation of the hepatic low-density lipoprotein receptor (LDLR), which regulates circulating cholesterol levels. Consequently, the PCSK9 inhibition is a valuable therapeutic approach for the treatment of hypercholesterolemia and cardiovascular diseases. In our studies, we discovered Rim13, a polyimidazole derivative reducing the protein–protein interaction between PCSK9 and LDLR with an IC50of 1.6 μM. The computational design led to the optimization of the shape of the PCSK9/ligand complementarity, enabling the discovery of potent diimidazole derivatives. In fact, carrying out biological assays to fully characterize the cholesterol-lowering activity of the new analogues and using both biochemical and cellular techniques, compound Dim16displayed improved PCSK9 inhibitory activity (IC500.9 nM). Interestingly, similar to other lupin-derived peptides and their synthetic analogues, some compounds in this series showed dual hypocholesterolemic activity since some of them complementarily inhibited the 3-hydroxy-3-methylglutaryl coenzyme A reductase.

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Light transmission aggregation (LTA) is used widely by the clinical and research communities. Although it is a gold standard, there is a lack of interlaboratory harmonization.

Deficiency in 25-hydroxyvitamin D (25OHD), the main circulating form of vitamin D in blood, could be involved in the pathogenesis of acute coronary syndromes (ACS). To date, however, the possible prognostic relevance of 25 (OH)D deficiency in ACS patients remains poorly defined. The purpose of this prospective study was to assess the association between 25 (OH)D levels, at hospital admission, with in-hospital and 1-year morbidity and mortality in an unselected cohort of ACS patients.

Introduction:The usefulness of anticoagulation in patients with atrial fibrillation (AF) is well known. However, the inherent limitations of vitamin K antagonists (VKAs) have made the development of new oral anticoagulants necessary. Drugs directed against thrombin or the factor Xa are currently available.Areas covered:These molecules, being administered at fixed doses and not requiring laboratory monitoring, overcome one crucial problem associated with the use of VKAs. However, data about the bleeding risk related to the use of these molecules should be further analyzed.Expert opinion:The efficacy of direct anticoagulants (DACs) in AF-related stroke prevention has been considered the primary outcome in all Phase III published trials. On the other hand, the reduction of the bleeding risk is an important goal achieved by the DACs as compared with VKAs. Besides data deriving from randomized trials, when talking about new drugs, the need of evidences from the ‘everyday clinical practice' are often requested. The aim of this literature revision is to report and analyze data from specific subgroups about which little is known. In particular, information about the use of DACs in oncologic patients, in patients receiving concomitant antiplatelet drugs and in the perioperative period is currently lacking. The parallel evaluation of all these data may lead to the identification of clinical and demographical criteria to choose when to switch to DACs.

Ischemic stroke is the third most common cause of death and of long-term disability and exhibits a high recurrence rate. Therefore, appropriate primary and secondary prevention is mandatory. In non-cardioembolic stroke, in addition to lifestyle changes and to targeted treatments, current guidelines recommend antiplatelet treatment. In cardioembolic stroke, Vitamin K antagonists (VKAs) are recommended. Although a favorable risk/benefit ratio of both treatments has also been demonstrated in elderly patients, registry data emphasize that such interventions are often under-used, especially in patients with atrial fibrillation (AF). Furthermore, variability in the inter-individual response to drugs has been recognized as a leading cause of event recurrence. Thus, in addition to poor adherence, efficacy and safety issues appear to be involved in the recurrence rate of stroke. In this review, we report main Registries data on adherence to stroke prevention treatment schedule. We also discuss the major limitations of “traditional” antithrombotic drugs and report Phase III study results on safety and efficacy of new antiplatelet and anticoagulant drugs, with emphasis on stroke prevention.

To investigate the ability of statins, the inhibitors of the hydroxymethylglutaryl–coenzyme A reductase enzyme, to affect endothelial cell activation induced by anti–β2-glycoprotein I (anti-β2GPI) antibodies in vitro. Human umbilical vein endothelial cell (HUVEC) activation was evaluated as U937 monocyte adhesion, E-selectin, and intercellular adhesion molecule 1 (ICAM-1) expression by cell enzyme-linked immunosorbent assay and as interleukin-6 (IL-6) messenger RNA (mRNA) expression by RNA protection assay. E-selectin–specific nuclear factor κB (NF-κB) DNA-binding activity was evaluated by the gel-shift assay. HUVECs were activated by polyclonal affinity-purified IgG, human monoclonal IgM anti-β2GPI antibodies, human recombinant IL-1β, tumor necrosis factor α, or lipopolysaccharide (LPS). Fluvastatin reduced, in a concentration-dependent manner (1–10 μM), the adhesion of U937 to HUVECs and the expression of E-selectin and ICAM-1 induced by anti-β2GPI antibodies as well as by cytokines or LPS. Another lipophilic statin, simvastatin, display similar effects but to a lesser extent than fluvastatin. The inhibition of E-selectin expression exerted by fluvastatin was related to the impairment of NF-κB binding to DNA. Moreover, the drug attenuated the expression of IL-6 mRNA in HUVEC exposed to anti-β2GPI antibodies or cytokines. Incubation of HUVECs with mevalonate (100 μM), concomitantly with fluvastatin, greatly prevented the inhibitory effect of statin. Endothelial activation mediated by anti-β2GPI antibody can be inhibited by statins. Because of the suggested role of endothelial cell activation in the pathogenesis of antiphospholipid syndrome (APS), our data provide, for the first time, a rationale for using statins as an additional therapeutic tool in APS.